In this image taken from video, which has been authenticated based on its contents and other AP reporting, Free Syrian Army fighters captured a helicopter at the Marj al-Sultan military air base in Damascus, Syria, on Wednesday, Nov. 28.

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Syrian opposition forces have reportedly captured part of the road to the Damascus airport in fighting today, bringing opposition forces closer to besieging the capital.

Rebels say the violence has forced the closure of the entire Damascus International Airport, while Dubai’s Emirates airline announced that it is indefinitely suspending all flights to and from the Syrian capital. In a statement on the airline’s website it wrote that “the safety of our passengers and crew is of the highest priority and will not be compromised.”

The rebel assault near the airport may indicate that opposition forces are getting closer to besieging the capital city and now pose a greater threat to the military’s air force, both of which are major steps toward the removal of President Bashar al-Assad.

“The regime is already thinking in terms of siege mentality in Damascus, but the rebels are also not in a position to dislodge the regime yet,” says Joseph Holliday, a senior research analyst at the Institute for the Study of War who specializes in Syria.

But their push on Damascus will likely bolster their efforts elsewhere in the country by keeping regime forces focused on the capital.

“The regime still has a much higher preponderance of troops in Damascus than anywhere else in the country. The rebels are strong enough there that it will prevent the regime from deciding to reinforce the north or something like that because they need everything they’ve got in Damascus,” adds Mr. Holliday.

Already there are reports that the government is massing weapons and supplies in Damascus, preparing for a heavy battle to defend it. The regime also took a significant step today when it shut down the Internet, dealing a blow to opposition forces and activists who rely on the Web to coordinate their activities, though some rebel elements have been given gear from the US to run their own communications separate from the government's network.

Forces loyal to the embattled president may also be ratcheting up activity after opposition fighters managed to down a helicopter and a jet this week, reportedly using surface-to-air missiles.

The regime military has used its air force as a tool to strike opposition forces with relative impunity throughout the war. However, the rebel groups have recently acquired antiaircraft missiles and created increasingly effective antiair defenses using heavy machine guns.

Until this week, the group had not yet downed a jet using a shoulder-launched, surface-to-air missile called a MANPAD, but two days ago rebels downed a helicopter and yesterday they downed a fighter jet. The Free Syrian Army has likely had such weapons since at least late this summer that were either captured from the Assad regime or brought from outside suppliers.

“It isn’t exactly new that they’ve got them. What’s new is that they appear to have ones that can actually shoot something down and they know how to use them,” says Jeffrey White, a defense fellow at the Washington Institute for Near East Policy. “It isn’t a decisive moment in the war. It’s part of a process of accumulating increasing rebel military capabilities and declining capabilities for regime forces."

It is still too early to tell if opposition forces will be able to duplicate their success against government aircraft using the missiles. But this week's incidents are a serious morale boost for the rebels; and if they become a trend, it will be a strategic leg up for rebels who have long cited government jets as a huge challenge to advancing against government troops.